In March 1989, more than 28 years ago, Sir Tim Berners-Lee unveiled his vision for what would later be named the World Wide Web (WWW) in a document called Information Management: A Proposal (http://info.cern.ch/Proposal.html). Since then, the WWW has grown to be a tool of information, communication, and entertainment for more than two of every five people on our planet.

The first version of the WWW relied exclusively on web pages and hyperlinks between them, a concept kept until present times. It was mostly read-only, with limited support for interaction between the user and the web page. Brick and mortar companies were using it to put up their informational pages. Finding websites could only be done using hierarchical directories like Yahoo! and DMOZ. The web was meant to be an information portal.

This, while not being Sir Tim Berners-Lee's vision, allowed media outlets such as the BBC and CNN to create a digital presence and start pushing out information to the users. It revolutionized information access as everyone in the world could get first-hand access to quality information at the same time.

Web 1.0 was totally device and software independent, allowing for every device to access all information. Resources were identified by address (the website's URL) and open protocols (GET, POST, PUT, DELETE) could be used to access content resources.

Hyper Text Markup Language (HTML) was used to develop web sites that were serving static content. There was no notion of Cascading Style Sheets (CSS) as positioning of elements in a page could only be modified using tables and framesets were used extensively to embed information in pages.

This proved to be severely limiting and so browser vendors back then started adding custom HTML tags like <blink> and <marquee> which lead to the first browser wars, with rivals Microsoft (Internet Explorer) and Netscape racing to extend the HTTP protocol's functionality. Web 1.0 reached 45 million users by 1996.

Here is the Lycos start page as it appeared in Web 1.0 http://www.lycos.com/:

Yahoo as appeared in Web 1.0 http://www.yahoo.com:

A term first defined and formulated by Tim O'Reilly, we use it to describe our current WWW sites and services. Its main characteristic is that the web moved from being read-only to the read-write state. Websites evolved into services and human collaboration plays an ever important part in Web 2.0.

From simple information portals, we now have many more types of services such as:

• Audio
• BlogPod
• Blogging
• Bookmarking
• Calendars
• Chat
• Collaboration
• Communication
• Community
• CRM
• E-commerce
• E-learning
• Email
• Filesharing
• Forums
• Games
• Images
• Knowledge
• Mapping
• Mashups
• Multimedia
• Portals
• RSS
• Wikis

Web 2.0 reached 1+ billion users in 2006 and 3.77 billion users at the time of writing this book (late 2017). Building communities was the differentiating factor for Web 2.0, allowing internet users to connect on common interests, communicate, and share information.

Personalization plays an important part of Web 2.0 with many websites offering tailored content to its users. Recommendation algorithms and human curation decides the content to show to each user.

Browsers can support more and more desktop applications by using Adobe Flash and Asynchronous JavaScript and XML (AJAX) technologies. Most desktop applications have web counterparts that either supplement or have completely replaced the desktop versions. Most notable examples are office productivity (Google Docs, Microsoft Office 365), Digital Design Sketch, and image editing and manipulation (Google Photos, Adobe Creative Cloud).

Moving from websites to web applications also unveiled the era of Service Oriented Architecture (SOA). Applications can interconnect with each other, exposing data through Application Programming Interfaces (API) allowing to build more complex applications on top of application layers.

One of the applications that defined Web 2.0 are social apps. Facebook with 1.86 billion monthly active users at the end of 2016 is the most well known example. We use social networks and many web applications share social aspects that allow us to communicate with peers and extend our social circle.

It's not yet here, but Web 3.0 is expected to bring Semantic Web capabilities. Advanced as Web 2.0 applications may seem, they all rely mostly on structured information. We use the same concept of searching for keywords and matching these keywords with web content without much understanding of context, content and intention of user's request. Also called Web of Data, Web 3.0 will rely on inter-machine communication and algorithms to provide rich interaction via diverse human computer interfaces.